Multiple bond for signal-service track-circuit rails



4 Oct. 2, .1923.

- 1,469,302 ,c. o. HARRINGTON I MULTIPLE BOND FOR SIGNAL SERVICE TRACK. CIRCUIT RAILS Filed Sept. 24.1920

16 z 11 1 12 8 *Izi i if 5: 17 In 915; f IQYZQ Patented Get. 2, 1923..

sense srarnfls onr'n'ron 0. nnnnrne'ronforonircneo, rnrirnois, Assiernon To ALDOBILT- ooMPAnY,

or CHICAGO, ILLINOIS, aconronnrron or ILLINOIS.

MULTIPLE BOND non SIGNAL-SERVICE TnAcK-crnoUIrnAILs.

' Application filed September 24,1920 Seria1:No.'412,540',

To all whom it may concern: Be it known that I, CLINTON O. I'IARRING- TON, a citizen of the United States, and a resident of Chicago, in the. county of Cook electric circuit for operating track signals For various reasons 1th at a distant point. is highly desirable that the abutting ends of the rails be connected together by bonds oflow electrical resistance. F or many years the ordinary practice has been to provide a 'moderately low resistance bond at the signal-service track rail oints-one which has a resistance deemed about low enough for practical purposes, but which would.

be made of much lower resistance were it not for the'increase of objections incident thereto. That formof connection consists in bonding two solid copper wires at their ends to the respective end portions .of the abutting track rails, the wires-extending from end to end and beyond theends of the fish plate, and is the only'ii'orm of mul tiple bonding for s'ignal-service-track-circuit rails of which I am aware, Such bonding has the important advantages of easy 1n spection and repair; but it has the impor= tant disadvantages of relatively high cost, notable, susceptibility to breakage at the points of bonding to the" rail, marked sus-I ceptibility to breakage by misdirected blow of the spike-maul, tamping tools, etc., of the track workman, a strong inducement offered for theft of the valuable copper,

'which "inducement is heightened by the simplicity of its removal by means of clippers, and, in addition, such a bond does not provide the deslred low resistance, but

only so low a resistance as is obtainable in that way within reasonable costs.

In electric railway practice, where the rails are bonded together to form a circuit for'the high tension current used for operating the cars it has been found feasible to provide a relatively short bond of low electrical resistance, usually of strands of copper wires in cable fo'rm, with the ends oft-he bond connected to the rails quite close to theirv abutting ends and located under the fishplate, the ends of the conductor being secured to the rails respectively by awelding operation or bywedging pins. In railway signal-track circuits, however, the practice of placing such a short'lo-w-resistance bond underv the fish plate has not obtained, for the safety of property and life JIl railway traffic depends so strongly upon the integrity of the signal system that the possibility of constant inspection of the bonds and their ready repair when damaged or broken is a"paramount consideration and has, prior tomy invention, prohibited the use of the short low-resistance bond-locatedout of sight and out of ready accessibility, as beneath the fish plate.

. In view of the monetary value oi copper, its conductivity, and the comparative ease with which it may be broken, the location of a shortvlow-resistance copper bond where it 'is'safe from' all attack,- intentional or otherwise, as between the fish plate and the web of the rail, is substantially ideal.

Owing to. the hitherto considered imprac 'ticabilityof locating such a bond-behind the fish plate in railway signal practice it has been suggested to employ the same kind ofa short low resistance copper bond provided with terminal pieces which are weld ed upon the sides of the rail heads near the WE T; me's;

joint. While this form of bond gives the I desired low resistance it is subject to the important objections of requiring-the use of a 'considerable amount of special apparatus and equipment in the field both'for the original installation and from time to time in: replacing the bonds which become broken, and such-bonds are highly susceptible to breakage due to their location'near the top of the rail where'ithey are readily struck by downhanging parts of passing trains.

'Another objection is in the fact that the downhanging loop" of conductor overlies the fish plate and interferes withthe removal of theJfishJ plate and when the fish plate is removeditheconductor is likely to bebent.

Furthermore, owing to its exposed position the conductor must be made considerably heavier than is necessary for the electrical purposes.1nvolved,,and, also, the value of prior methodsf s hereinabove pointed out,, and this is accomplished through the provision of a low-resistance bond comprising a relatively short conductor: electrically bonded to the abutting end portions of the rails and located at a substantially inacces-- sibleplace, as between the fish plate andfthe web of the rail, together with an auxiliary bond, atleast the connections of-whichito the rai-lsareoutside the fish plate and where the connectionscan-be readily inspected and repaired, which auXiliary'c-onductor maybe of low-grade and substantially inexpensive wire such as, iron, the auxiliary conductor i being bonded to. the rails preferably near 7 the ends. of the fish plate. Through these provisions the continuity of: the service is bound to be maintained; under'all of. the

ordinary conditions of use. Z

In the accompanyingdrawings Which form a partof this specification, Figure. 1

is fragmentary face view of. two abu ting track rails constituting part ofj the. sig-v nal circuit, with thetfish, plate at the rail joint brokenaway to show the otherwise cone.

clealed bond; and. Fig.- 2: is vertical.- cross section as on theline 2-2 of Fig. 1.

The rails lO and- 1'1, thefish plate 12 and thebolts 13 may be ccording,towell known construction. isshown as a short section ofrstrandediwire, preferably copper, and, may consist of; 20

or 30 strands and have a total diameter of.

three-sixteenths of an inch. The. ends of theconductorll; are shown as being secured to plugs or wedging pins 15-, as byljbrazing or soldering, a side view of'one pin being in Fig. 2. The plugs 15. are frictionally driven tightly into holes in the Web ofthe rail, making electrical connection therewith. The bond between the conductor letand the rail may be according to any, approved form.

The auxiliaryor. safety conductor 16 may lJG-CODSlClGlQCl to be a section of ordinary. iron wire, say five thirty-seconds. of an inch in diameter.- rail by wedging 13111-117 at one end; and 18 at the other end, the wire 16 being preferably soldered to the pin, the form ofbondshown at 17' and 18v being the same as that shown at 15. In this. instance: also the conductor l6.may be electrically bonded to the rail in any approved-way.

From this construction and arrangement The low resistance bond it It is electrically bonded to the it is clear that the track-walker or maintainer of the system may readily detect any defect in the bonding of the j auxiliary or safety conductor 16 and, with the small tools usually carried forthe purpose, the auxiliary bond, if broken, may be restored The chief interest of the maintainerof the system from time to time therefore is to see that the auxiliary bond is intact, for so long as the auxiliary or safety bond is sound there will be no failure of thesystein. Although the bond 16 has relatively high resistance, yet the occurrence of: as-many as twenty such high. resistance bonds operating 7 severally aloneat as many joints in the circuit at a time when at the other large number of joints in the track thelow-resistance bonds are in operation would not materially affect the satisfactory operation of" the signals. V r r Furthermore, owing to the secluded posi-. tion of the low-resistance bond. li'and the protection. afl'orded it: bythe rail and fish plate the danger ofv its breakage or other failure is reduced to the minimum and failures of this bond would occur butseldom. and? to I only a limited numerical; extent be.- tween one complete inspection and another, say once a year.

Without the auxiliaryrbond' the placing-ofthe low-resistanceconductor in a concealed; place such as behind: the fish plate would be fraught with much danger, for in: case of. the failure of one such. bond out. of say three hundred in the circuit the signal v would: in all. likelihood fail. Tolocate the particular bondbroken would requirean inspection with an instrument ofeach, joint: untilthe broken one isfound, and; then the ofttimes very difficult; operation of remov-v ing the fish plate would:havetobe resorted to before the circuit could be restored; all

involving muchwexpense: and seriously; in-. terfering with. the. use of the track for a considerable period: Of time. According to these improvements all such: danger is! be readily. discovered and repaired, and; repairs to any of the low-resistance bonds may be made at any convenient; time.

Inasmuch asthe iron wirelfi would. seldom if ever bebroken exceptat the con nections. of it to the. rails, this wire may, also lie for themost part under. the, fish plate or be other-wiseconcealed, but-it. is essential-that at leastthe connections thereof.-

avoided, the safety bond; when brokemcan;

to the railsibeopen, and rea'dily, tobe. in-

spected and repaired;

I contemplate also as invention suclr variations and departures from what isspecifically illustrated and described as are'included-in the scope of the:

appended claim.

I claim The combination of two signal service beingwithin. my 7 track rails abutting each other end to end, tively' coveredby the rail parts, and an auxa fishplate and bolts holding the rails toiliary conductor having its end portions gether, a relatively short low electrical reelectrically bonded to the rails respectively 1 sistance conductor electrically bonded td at places respectively Where the connections a each rail near the abutting ends thereof and are open to ready inspection and repair. located at a relatively diflicultly accessible part of the rails respectively and protec- CLINTON O. HARRINGTON. 

